Indian summer monsoon rainfall drives Antarctic climate and sea ice variability through atmospheric teleconnections

Abstract

In recent decades, Antarctica has undergone significant climate change, with most studies focusing on the impact of oceanic multiscale variability on Antarctica, especially on West Antarctica. However, our research reveals that Indian summer monsoon (ISM) rainfall strongly influences the austral winter (June–August) Antarctic climate and sea ice concentration (SIC) through atmospheric teleconnections. Diabatic heating from ISM rainfall shifts the Hadley cell northward, triggering a Rossby wave train from the Mascarene Islands into Antarctica. This alters sea level pressure and induces warm advection to both East and West Antarctica, leading to widespread warming. Consequently, Antarctic SIC undergoes a tripole redistribution, with increases in the Ross and Weddell Seas, and decreases in the Amundsen and Bellingshausen Seas. These findings emphasize the importance of ISM rainfall in shaping Antarctic climate and SIC, suggesting ISM rainfall as a possible contributing factor to the record-low Antarctic SIC observed during the austral winter of 2023.